Revealingly, however, as the killer’s suspected identity metamorphosed, so both the ‘lessons’ to be learned, and the identity of those stepping forward to teach them, changed just as fast. This should tell us something important.

Initial reports had suggested that the killer was a Neo Nazi with links to groups on the far Right. Certainly, given the racial profile of those he killed, this was plausible. The three French soldiers he murdered last week were of North African or Caribbean origin, and a neo-Nazi attack on a Jewish school would also not be difficult to comprehend. One witness of the school shootings said she saw a tattoo on the killer’s face beneath his mask, and links were drawn with three French paratroopers ejected from the army in 2008 for their racist activities, which included executing a salute in front of a swastika flag.

No sooner was this connection made than efforts to contextualise the killer’s actions on this basis began in earnest. At the forefront was François Hollande, the socialist candidate in this year’s French presidential elections, who accused President Sarkozy and the far-right candidate Marine Le Pen of fostering a climate of intolerance towards foreigners in France.

“There are words that influence, that penetrate, that free up”, said M. Hollande, referring to recent speeches by President Sarkozy and Mme Le Pen on immigration. “Those who have responsibility must master their vocabulary”.

Joining M. Hollande in these insinuations was François Bayrou, the centrist presidential candidate, who claimed that the murder of children “because of their origin, of the religion of their family” could be linked “to a growing climate of intolerance” in France.

The message of both men could not have been clearer. France, and the French political right in particular, bore some responsibility for these crimes, and greater tolerance towards immigrants was therefore needed if similar incidents were not to happen again.

Barely had this lesson been proffered, however, than police reported that they suspected the killer of having an altogether different identity. He was not a skinhead after all, but Mohammed Merah, a 24-year old French citizen of Algerian extraction with suspected links to al Qaeda. Just as his identity changed, so his suspected motives and the lessons France needed to learn from them changed also. The soldiers had been killed not because they weren’t white, but because they had fought for France in Afghanistan. The Jewish children were killed to avenge the deaths of Palestinian children killed by Israeli forces in Gaza and the West Bank.

In a flash, Marine Le Pen was off the ropes and into the centre of the ring: “It is time to wage war on these fundamentalist political groups who are killing our children”, she thundered. “The fundamentalist threat has been underestimated. Security is a theme that has just signed up to the presidential campaign”.

The French, however, have not been alone in their opportunism. From the British far-left came Lindsey German, head of the UK’s Stop the War Coalition, who offered an altogether different narrative. “Islamophobia is not some aberration in France: it stems directly from the support for imperialist wars and the legacy of colonial rule.” Anti-Muslim racism, France’s involvement in Afghanistan, and the legacy of French rule in Algeria were in fact to blame. The lesson? End these wars and clamp down on the racism, and such killings will not so likely happen again.

How extraordinary. Exactly the same man committed exactly the same murders against exactly the same people. What changed was not the man, but who those watching suspected him to be. So too his ‘agenda’, understood as a reaction to supposed aggravating factors generated by others.

The point here should be clear: it is far too easy to shift responsibility away from the man and onto the environment in which he operates, and to advance a given political agenda accordingly.

This is not to argue that context has no bearing on peoples’ thoughts and actions, but it is to argue that when those thoughts and actions are carried into the realm of cold-blooded murder, context should never be used as an excuse, and it should be used to argue for a change in this or that policy only very rarely.

One person may feel very strongly that the war in Afghanistan is wrong. Another may feel equally strongly that anti-immigrant rhetoric is unhelpful. Neither should seek to use the actions of such a man as this for justification of their arguments. It is quite possible to disagree with something in the strongest terms and not turn to the gun to settle the dispute. That, indeed, is the essence of democracy.

Knee-jerk alterations to entire policy areas in response to such crimes is not only bad strategy, it is also dangerous. That, if anything, should be the first lesson of this terrible episode, and the second stems from it: this man, and this man alone, is responsible for his crimes. French policy on immigration, Afghanistan or whatever else does not come into it.